Incandescent lamp



No Model.)

. X a c 0% UNITED STATES PATENT OFFICE.

GEORGE R. LEAN, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE BERN- STEIN ELECTRIC COMPANY, OF PORTLAND, MAINE.

INCANDESCENT LAMP.

SPECIFICATION forming part of Letters Patent No. 431,776, dated. July 8, 1890.

Application filed April 4, 1890. Serial No. 346,505. (No model.)

To all whom it may concern:

Be it known that I, GEORGE R. LEAN, of Boston, county of Suffolk, State of Massachusetts, have invented an Improvement in Incandescent Lamps, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawing representing like parts.

This invention has for its object to provide an incandescent lamp with improved means for preventing too great vibration of the filament, it being especially adapted for lamps used in railway-cars, elevators, and similar places. The means heretofore provided for this purpose have consisted of metallic posts and the like arranged at each side of the outer or loop-like end of the filament, being secured to the bulb interiorly at the apex thereof. hen, however, a lamp is turned on and the filament glows, frequent contact with these metallic posts soon weakens the filament, removing, as it does, small particles at a time, and the life of the filament is materially reduced; also, I have found that the filaments by their frequent contact with metallic posts form grooves in said posts by melting away the material. In my experiments to produce a stop or stops which shall effectually accomplish the desired result and at the same time insure the full life of the filament, I have found that the stop or stops must be made of material which will not melt and that is noncombustible; and, furthermore, that a stop or stops composed of the same material of which the filament is made are best suited for the purpose. I have therefore provided stops made of carbon, they being secured to the apex of the bulb located adjacent to each other to receive between them the filament. lVhen the airis exhausted from the bulb, a small short tube of glass is fitted in the hole. at the end, the outer end of which tube is afterward closed or sealed, and to secure the stop or stops in place I have closed the inner end of this tube and'secured the stops in said closed end, and have provided the tube with an inlet or air-hole at one side.

The drawing shows in vertical section an incandescent lamp constructed in accordance with this invention.

The-bulb a, is formed in usual shape and construction, it having at its enlarged end a hole. A short glass tube is fitted in said hole, being welded to the bulb. This glass tube is closed at its inner end, as at 1), into which end stops 0 c are fixed, they being pressed into the said end when the glass is in a molten condition. An air-hole b is provided at one side of the glass tube within the bulb. The outer end of the glass tube 17 is closed after the air has been exhausted in usual manner.

The stops 0 c are made of carbon of the same material as the filament, and the loop like end of the filament lies between these two stops, so that as it is vibrated it will strike one or the other stop 0 or 0'. These stops being made of the same material as the filament will not melt by contact therewith, and will not act on and injure the filament to reduce the length of its life.

I claim In an incandescentlamp, the bulb and short tube 1), closed at its inner end, and having fixed to it the stops 0 c and an air-hole b at one side of the said short tube, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

GEORGE R. LEAN.

Witnesses:

BERNICE J. NoYEs, EMMA J. BENNETT. 

